This invention relates to an invalid hoist.
It is known from GB-A-2323348 to provide an invalid hoist comprising a mobile chassis, a mast upstanding from the chassis, a lifting arm pivotably connected to the upper end of the mast, the lifting arm having a sling hanger or at least one sling attachment point at or adjacent to one end thereof, a power operated extendible/retractable actuator between the lifting arm and the lower part of the mast, the lifting arm being pivotably connected to the upper end of the mast at a position intermediate its ends and the actuator being connected to the lifting arm on the side of the pivotable connection between the lifting arm and the mast remote from said one end of the lifting arm, and a link pivotably connected between one end of the actuator and either the lifting arm or the mast so that if the lifting arm meets with an obstruction during a lowering operation, the actuator and link will pivot relative to one another so that the actuator can continue to extend without applying a force to the lifting arm to urge the latter against the obstruction.
It is often a requirement to be able to weigh a patient and it is convenient to do this while the patient is supported by an invalid hoist as this saves both time and effort. However, it is expensive to provide every hoist with a load cell, for example in the lifting arm or the mast.
The present invention seeks to overcome this problem.
According to a first aspect of the present invention, there is provided an invalid hoist comprising a mobile chassis, a mast upstanding from the chassis, a lifting arm pivotably connected to the upper end of the mast, the lifting arm having a sling hanger or at least one sling attachment point at or adjacent to one end thereof, a power operated extendible/retractable actuator between the lifting arm and a lower part of the mast, the lifting arm being pivotably connected to the upper end of the mast at a position intermediate its ends and the actuator being connected to the lifting arm on the side of the pivotable connection between the lifting arm and the mast remote from said one end of the lifting arm, and a connecting link pivotably connected between one end of the actuator and the lifting arm (or the mast) so that if the lifting arm meets with an obstruction during a lowering operation, the actuator and link will pivot relative to one another so that the actuator can continue to extend without applying a force to the lifting arm to urge the latter against the obstruction, wherein the connecting link is connected between said one end of the actuator and the lifting arm (or the mast) such that an auxiliary link incorporating a load cell can be additionally and removably connected between said one end of the actuator and the lifting arm (or the mast) and such that any load then applied to the lifting arm is transmitted entirely through the auxiliary link and not through the connecting link.
According to a second aspect of the present invention, there is provided an invalid hoist as claimed in any one of the preceding claims, in combination with an auxiliary link incorporating a load cell.
It is thus possible to supply one or a small number of auxiliary links, each incorporating a load cell, for use with a much larger number of hoists. The auxiliary link may then be used only when needed.
The invention will now be more particularly described, by way of example only, with reference to the accompanying drawings.